Abstract

Lactate dehydrogenase (LDH: 3.1.1.27) is a tetrameric enzyme participates in carbohydrate metabolism by catalyzing the oxidation of lactate and reduction of pyruvate. The random tetramerization of LDH-A and -B subunits leads to the formation of five tetramers: LDH-B4, LDH-A1B3, LDH-A2B2, LDH-A3B1 and LDH-A4. Due to the biochemical and evolution-ary significance of LDH isoenzyme characters or LDH genes, efforts are made here to pro-pose a numerical coding method of quantifying the isoenzyme activities and demonstrate the presence of LDH loci or the changing levels of isoenzymes in different tissues of selected air-breathing teleosts Channa punctata, C. gachua and C. striatus. Polyacrylamide gel electro-phoretic (PAGE) profiles of LDH isoenzymes were utilized and software analysis of gel scans was performed. Our results show a great variation in the quantitative as well as quali-tative presence of isoenzymes or their genes among the selected freshwater congeneric spe-cies. Based on the obtained results, adaptive strategies of Channa species are discussed in re-lation to their evolutionary set up.